package com.fysports.framework.kit.security;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;


/**
 * RSA对称加密算法
 * Created by konbluesky
 * Date : 14-7-31 下午3:34
 * Project : JdmData_WebServer
 */
public class RSAKit {
    /**
     * 加密
     *
     * @param publicKey
     * @param srcBytes
     * @return
     * @throws NoSuchAlgorithmException
     * @throws NoSuchPaddingException
     * @throws InvalidKeyException
     * @throws IllegalBlockSizeException
     * @throws BadPaddingException
     */
    protected static byte[] encrypt(RSAPublicKey publicKey, byte[] srcBytes)
            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
            IllegalBlockSizeException, BadPaddingException {
        if (publicKey != null) {
            //Cipher负责完成加密或解密工作，基于RSA
            Cipher cipher = Cipher.getInstance("RSA");
            //根据公钥，对Cipher对象进行初始化
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            byte[] resultBytes = cipher.doFinal(srcBytes);
            return resultBytes;
        }
        return null;
    }


    /**
     * 解密
     *
     * @param privateKey
     * @param srcBytes
     * @return
     * @throws NoSuchAlgorithmException
     * @throws NoSuchPaddingException
     * @throws InvalidKeyException
     * @throws IllegalBlockSizeException
     * @throws BadPaddingException
     */
    protected static byte[] decrypt(RSAPrivateKey privateKey, byte[] srcBytes)
            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
            IllegalBlockSizeException, BadPaddingException {
        if (privateKey != null) {
            //Cipher负责完成加密或解密工作，基于RSA
            Cipher cipher = Cipher.getInstance("RSA");
            //根据公钥，对Cipher对象进行初始化
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            byte[] resultBytes = cipher.doFinal(srcBytes);
            return resultBytes;
        }
        return null;
    }


    /**
     * @param args
     * @throws NoSuchAlgorithmException
     * @throws BadPaddingException
     * @throws IllegalBlockSizeException
     * @throws NoSuchPaddingException
     * @throws InvalidKeyException
     */
    public static void main(String[] args)
            throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException,
            IllegalBlockSizeException, BadPaddingException {
        String msg = "郭XX-精品相声";
        //KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        //初始化密钥对生成器，密钥大小为1024位
        keyPairGen.initialize(1024);
        //生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        //得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        //得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

        //用公钥加密
        byte[] srcBytes = msg.getBytes();
        byte[] resultBytes = RSAKit.encrypt(publicKey, srcBytes);

        //用私钥解密
        byte[] decBytes = RSAKit.decrypt(privateKey, resultBytes);

        System.out.println("明文是:" + msg);
        System.out.println("加密后是:" + resultBytes.toString());
        System.out.println("解密后是:" + new String(decBytes));
    }
}
